France has gone onto a full-scale alert to try to prevent the UK foot-and-mouth disease outbreak from spreading across the Channel.

All pigs, cows, sheep and goats imported from the UK in February are to be tracked down, under the emergency plan announced in Paris.

Any animals showing signs of the disease will be destroyed, according to a spokesperson from the Agriculture Ministry.

Discussions are still under way on what to do with animals, meat and other products which reached France before the EU's ban on UK exports came into effect.

Airborne fears

In the meantime, the government has appealed for farmers, customs officials, vets and even lorry drivers who transport animals to look out for signs of the disease.

But there are fears that the disease could also reach France indirectly, by being carried on the wind across the Channel.

Foot-and-mouth disease has previously been known to travel up to 250km (150 miles) if the right environmental conditions are in place, particularly a damp wind of the kind blowing across southern England in the days before the disease was discovered.

Computers are now being used to track the possible direction and distance which the virus could theoretically have travelled from the Essex abbatoir where it first came to light.

Agricultural show alert

The French Government has ordered detailed tracking information on the wind direction, say media reports.

Meanwhile a lorry carrying horses to an agricultural show in Paris has been turned back.

Blood tests are being carried out on English sheep which had already arrived for the fair.

The results will not be known until Monday, but a French spokesman for the UK's Meat and Livestock Commission says the animals did not come from the English regions known to have been affected by the disease.

A spokesman for the French pig industry - which imports around 5,000 live pigs from the UK every year - has also cautioned against panic over the situation.

French media reports point out that the new crisis represents a dramatic setback for farmers already badly affected by the BSE crisis.